Even in the context of the Who’s odd catalog, ”The Who Sell Out” is an oddity. Released in December 1967, the group’s third album is both an outlier and a bridge to the greatness that was to come, an unlikely collection of psychedelia, gentle heartbreak songs and neo-science fiction, all connected by a series of mock advertisements for everything from drums to deodorant performed by the group (hence the album’s title).

It’s a jarring contrast to both the smash-bang pop that launched the band and the rock gods they would soon become: The “sell out” conceit stretched to the cover, which featured singer Roger Daltrey sitting in a bathtub filled with Heinz baked beans and guitarist-songwriter Pete Townshend putting on a giant stick of deodorant. And at a time when the group was known for explosive live sets that ended with them smashing their equipment every night — not to mention the most explosive drummer in rock history, Keith Moon — it doesn’t rock very hard, either. With the exception of the glorious “I Can See for Miles” and some choice slabs of psychedelia, there are lots of acoustic guitars, stacked harmonies and gentle Townshend lead vocals interspersed amid the cheeky advertisements. For fans who came to the group after “Tommy” and “Who’s Next,” it was a mass of irony, psychedelia, bittersweet pop and a Britishness that didn’t have much to do with fist-pumping or teenage wasteland.

After the album’s initial release, the Who seemingly couldn’t move on from it fast enough: The songs were difficult to play live and the group rarely did (even weeks later, there were just two “Sell Out” songs in their setlist). In a hilarious 2018 interview, Daltrey couldn’t even remember what songs were on it.

However, time and some expert after-the-fact remixing of the original release’s muddy sound has allowed history to look more kindly on “The Who Sell Out,” revealing it as a masterpiece of melody and psychedelia. The album gave Townshend the experience of writing about things people don’t usually write songs about — from utopia to baked beans — which helped him to tackle some of the more absurdist themes in “Tommy” and his later, more earnest and quasi-spiritual works. It also saw him experimenting with ambitious song structures and arrangements and using the bandmembers’ ample talents in innovative ways.

Oddly, it starts with a cover — “Armenia City in the Sky” (which has nothing to do with the actual country of Armenia), written by Speedy Keen, singer and songwriter of Thunderclap Newman who’d had his own psychedelic anthem the previous summer with the Townshend-produced “Something in the Air” — before moving into the pretty whimsy of “Mary-Anne With the Shaky Hands” and “Tattoo,” the wistful “Our Love Was” and “I Can’t Reach You,” and some heaping dollops of psychedelia before concluding with the space-age “Rael.”

But anyone who’s read this far already knows all that: The question, as with all of the seemingly endless parade of elaborate archive-excavating reissues in recent years, is whether this sprawling 112-track extravaganza (with 47 of those tracks being previously unreleased), its 80-page book, new liner notes from Townshend and posters and 7” singles and whatnot, is worth the time and money. Eyes down.

Most importantly, the main album is presented in its most vibrant sonic setting to date, in both mono and stereo versions. There are subtle differences in the takes of certain songs (particularly with the guitars), and as usual, the mono mix is more compressed and punchier, while the stereo offers more depth and detail. Contemporaneous singles like “Pictures of Lily” and two Rolling Stones covers (recorded in a show of support during Mick Jagger and Keith Richards’ brief 1967 imprisonment on drug charges) and their B-sides, as well as multiple alternate takes and mixes, are included as well.

Most of the best outtakes — particularly the excellent “Melancholia” and “Early Morning, Cold Taxi,” and even some unreleased commercials — were released on previous editions but are essential parts of the package. The third disc is a “you are there” collection of studio outtakes and chatter that is largely for completists only, although there are intermittently fascinating items like yet another version of “Mary Anne With the Shaky Hands.” The fourth disc is called “The Road to ‘Tommy’” and collects virtually every studio recording the group completed during 1968, when they dashed off stopgap singles like “Magic Bus” and “Dogs” to feed the market while Townshend threw himself into writing the ambitious “Tommy.” Yet here, the songs are sequenced into a kind of mini-album that spans from the oddly morbid power-pop of “Little Billy” (an anti-smoking anthem written for and rejected by the American Cancer Society) and “Glow Girl” to the vaudevillian “Dogs” (a love song set at dog races) and the surf-pop of “Call Me Lightning.” Finally, the last disc collects Townshend’s demos from the era — again, largely for completists only, but it reveals just how much his bandmates brought when transforming them into Who songs.

It takes a deeply committed fan to dig into all 112 tracks here — in the “truth in advertising” category, there’s a raucous if directionless instrumental called “Sodding About” — and it’s hard to imagine most people needing to hear some of the titles here more than once. But this sprawling deluxe edition of “The Who Sell Out” is like a living museum of a group beginning to realize its greatness, and the thrill of their discovery — in 1967, no less — remains vivid 53 years later.